let buffer = new ArrayBuffer(8);//8个字节的ArrayBuffer
console.log(buffer.byteLength);//8
const int8Array = new Int8Array(buffer);
console.log(int8Array.length);//元素的长度 1个字节占用8个位
console.log(int8Array.buffer===buffer);
let int16Array = new Int16Array(buffer);
console.log(int16Array.length);//4